Arthroscopy is used to enter cavities in human or animal joints so as to work on the surface of a bone, for example. This work may be the smoothing of the surface. Further, arthroscopy is also useful in removing tissue, such as in the removal of bone parts from joints by milling, scraping and the like. In endoscopy, human tissue is treated in similar fashion; however, endoscopy is not employed in joint cavities but in any other part of the human or animal body.
With fractures of long tubular bones such as femurs, both bone parts are first aligned and then bored in the longitudinal direction. Subsequently, a nail is inserted into the bore to fix both bone parts.
The bore is provided by first inserting a guide pin into the bone marrow of both bone parts. The guide pin is a wire with a diameter of 2 to 3 mm. The guide pin serves to guide a drill head. The drill head is connected to a flexible shaft driven by a drill drive, such as a pneumatic drill.
When forming the bore, high pressure is generated at the drill head. This pressure pushes bone and fat tissue into venae. In this context, there is a chance of those particles being transported into the lung via the blood vessel and causing pulmonary embolism. In particular, if besides the bone fracture also the lungs are injured, the two bone parts cannot be fixed by the nailing describe above since the risk of pulmonary embolism would be too high. Thus, the bone can only be fixed from outside. As a consequence, the fracture often heals poorly, an proper anatomic setting of the fracture is difficult, infections of the soft-tissue environment occur frequently, and, possibly, the definite treatment of the fracture has to be performed in a second surgical operation.
CH 687 228 A5 discloses a special drill head for intermedullary reaming designed to reduce the pressure at the drill head. The drill head has openings through which the drilled material, primarily the bone marrow, can be transported rearward. However, since a flexible shaft is located in the drill hole, there is only little space for accommodating the drilled material. Thus, the amount of drilled material is larger than the space behind the drill so that the drilled material is further compressed. Thus, pressure builds up in the area of the drill head. This may result in drilled material being washed out into the lung via blood vessels and causing pulmonary embolism.
The problems of increased pressure build-up are also disadvantageous when endoscopes and arthroscopes are used and may cause the above mentioned problem, respectively.